In my previous U.S. Pat. No. 3,968,652, there is disclosed an apparatus for converting solar energy to mechanical and electrical energy wherein a refrigerant composition is alternately evaporated and condensed, and in which the evaporated composition is directed through conduits to drive a turbine or hydraulic motor. A pair of coils or pipes are used for alternately being exposed to the heating rays of the sun, the non-heated coil being cooled to condense the refrigerant composition. Although such a system is useful for the intended purpose, the present invention is directed to an improved system in which even more efficient conversion of such a solar energy evaporated refrigerant composition is achieved.